1. Field of the Invention
The present invention relates to an image-capturing device and diaphragm mounted in a device.
2. Description of the Related Art
An example of an image-capturing device is an active-system three-dimensional image-capturing device. An active-system three-dimensional image-capturing device which detects the three-dimensional shape of a subject, is disclosed in “Measurement Science and Technology” (S. Christies et al., vol. 6, p.1301–1308, 1995) and in International Publication No. WO 97/01111. In “Measurement Science and Technology”, a pulse modulated laser beam is divergently emitted to a measurement subject from a device and the reflected light from the subject is received by a two-dimensional CCD sensor to which an image-intensifier is attached, so that received light energy is converted to electric signals. The shutter operation is carried out with an image-intensifier which is controlled by a gate-pulse, and the gate-pulse is synchronized with the pulse radiation of the laser beam. According to the above construction of the device, the amount of light received during the exposure time at each pixel of the CCD relates to the distance between the pixel and the corresponding point on the subject, so that electric signals which correspond to the distance of the subject are obtained for each pixel of the CCD.
In International Publication No. WO 97/01111, a device divergently emits pulse modulated light, such as a laser beam, to a measurement subject and the reflected light is received at the two-dimensional CCD sensor which is assembled with a mechanical shutter or an electro-optical shutter formed by a liquid crystal display, so that received light energy is converted to electric signals. The shutter is controlled at a timing which is different from that of the laser emission and distance information of the measurement subject is obtained at each pixel of the CCD. Note that, signal charges obtained at each pixel of the CCD, which relate to the distance information, can be regarded as image signals. Therefore a set of image signals which corresponds to distance information or depth keying will be referred to as a three-dimensional image in the following. On the other hand, an image obtained by the CCD controlled in a normal video drive, an image which corresponds to visual information or chroma keying, will be referred to as a two-dimensional image.
A three-dimensional image of a subject is often used with a two-dimensional image of the subject which is taken from the same position. For example, a three-dimensional image can be utilized for background image processing of a two-dimensional image according to distance information or depth of the three-dimensional image. Further, the three-dimensional image can be used to calculate data for the three-dimensional shape of a subject and the two-dimensional image can be used for texture data of the three-dimensional data. In the above situation, it is preferable to capture a two-dimensional image and a three-dimensional image with the same photographing optical system. For example, a two-dimensional image and a three-dimensional image are sequentially taken by the same photographing optical system from the same position.